Doctors argue that the provisions gagged them from speaking publicly about conditions in Australian-run immigration camps on remote islands.

The doctors' legal team discovered in court documents this week that the government had exempted health professionals from the secrecy provisions shortly before lodging its legal defence, lawyer Meghan Fitzgerald said.

A government website shows that the change took effect on October 1, exempting a wide range of health professionals, including doctors, midwives, podiatrists and nutritionists.

"The government has been forced into a back down as a result of the advocacy of health professionals who owe a duty of care to ... their patients and whose ethical duties are paramount," Doctors 4 Refugees said in a statement.

Immigration and Border Protection Minister Peter Dutton did not immediately respond to a request for comment on Thursday.

The Border Force Act, which became law last year, makes it a criminal offence punishable by two years in prison for a broadly defined "entrusted person" within the immigration regime to disclose "protected information".

Fitzgerald said that the doctors were continuing their case, adding teachers and social workers who work with asylum seekers should also not be gagged by the threat of prison.

Under Australia's tough immigration policy, asylum seekers intercepted trying to reach the country by boat are sent for processing to a camp in Nauru or to Manus Island in Papua New Guinea, and are not eligible for resettlement in Australia.

Allegations of rights abuses

Several rights groups have released reports in recent weeks on rights abuses in one of Australia's offshore prisons for migrants and refugees on the island of Nauru.

Australia on Tuesday rejected a claim by Amnesty International that conditions on Nauru, where about 400 Australian-bound asylum seekers are held "amount to torture" .

Australian PM denies Nauru prison camp claims

Amesty's report came on the heels of an October 7 United Nations report accusing the governments of Australia and Nauru of failing to protect children held in detention.

Additionally, a UN human rights investigator said this w eek that Australia's government has become increasingly secretive through a range of new laws, including the gag on officials speaking out about conditions at Australia-run immigration camps in Nauru and Papua New Guinea.

Forst said he had been assured by government officials during his two-week visit to Australia that no one had yet been charged under the Border Protection Act.

"This may well be the case, but the Act's existence and government actions aimed at censoring and intimidating advocates has had a chilling effect on the disclosure of information about violations in off-shore processing," Forst wrote in his End of Mission Statement.